Abstract

The opening of the South Atlantic ocean at 110 Ma triggered the inversion of the Casma basin and the switch from marine volcanicity to plutonism, which evolved through three distinct phases. The first was the intrusion of the Coastal Batholith which forms a well-defined linear structure over the whole coastal region and which, in the Lima segment, endured from 100 to 60 Ma, and was terminated by the formation of the ring complexes. The second was the post Incaic development of the andesitic terrestrial plateau volcanics, the Calipuy group with associated scattered plutons of tonalite and granodiorite, which extended from perhaps 50 Ma to 20 Ma, and the third was the emplacement of the high level stocks and associated ignimbrite sheets from 20 to 6 Ma. Of these the Cordillera Blanca batholith which is of trondhjemitic affinity is the most important, and it is the intrusives of this zone which are the most important economically. Many plutons within the Batholith were emplaced into the brittle crust by processes of magmatic stoping and some of the evidence for this process is presented.

Purchase access

You may purchase access to this article. This will require you to create an account if you don't already have one.

LIBRARY USERS

Log in through your institution

You may be able to gain access using your login credentials for your institution. Contact your library if you do not have a username and password.

If your organization uses OpenAthens, you can log in using your OpenAthens username and password. To check if your institution is supported, please see this list. Contact your library for more details.